A developing cartridge includes a developing roller, and a casing in which a toner is accommodated. The developing cartridge is attachable to and detachable from an image forming apparatus.
Prior art discloses a developing cartridge provided with a developing electrode which is electrically connected to a shaft of the developing roller. More specifically, the developing electrode includes a sleeve portion and a bearing portion. An electrode of the image forming apparatus can contact with the sleeve portion. The shaft of the developing roller is inserted into the bearing portion. The developing cartridge further includes a gear rotatable about the sleeve portion and a protrusion rotatable together with the gear.